Astigmatism and Your Eyes

In this article

What Is Astigmatism?

Astigmatism is a common eye condition that's usually corrected by eyeglasses, contact lenses, or surgery.

Astigmatism is caused by an eye that is not completely round and occurs in nearly everybody to some degree. For vision problems due to astigmatism, glasses, contact lenses, and even vision correction procedures are all possible treatment options.

A person's eye is naturally shaped like a sphere. Under normal circumstances, when light enters the eye, it refracts, or bends evenly, creating a clear view of the object. However, the eye of a person with astigmatism is shaped more like a football or the back of a spoon. For this person, when light enters the eye it is refracted more in one direction than the other, allowing only part of the object to be in focus at one time. Objects at any distance can appear blurry and wavy.

What Causes Astigmatism?

Astigmatism is a natural and commonly occurring cause of blurred or distorted vision that is usually associated with an imperfectly shaped cornea. The exact cause in not known.

What Are the Symptoms of Astigmatism?

People with undetected astigmatism often have blurred vision which can be associated with fatigue and eyestrain. While these symptoms may not necessarily be the result of astigmatism, you should schedule an eye exam if you are experiencing one or more symptoms.

How Is Astigmatism Diagnosed?

Your eye doctor can diagnose astigmatism with a thorough eye exam. Astigmatism may occur with other vision problems such as nearsightedness and farsightedness. Because astigmatism may increase slowly, you should visit your eye doctor whenever you notice changes in your vision.

How Is Astigmatism Treated?

Almost all degrees of “normal” astigmatism can be corrected with properly prescribed eyeglasses or contact lenses. For a person with only a slight degree of astigmatism, corrective lenses may not be needed at all, as long as other conditions, such as nearsightedness or farsightedness, are not present. If the astigmatism is moderate to high, however, corrective glasses or contact lenses are probably needed.

Irregular astigmatism is far less common and is associated with abnormal conditions affecting the cornea (for example, keratoconus). This condition is more effectively treated with rigid gas permeable contact lenses or corneal procedures.

Corrective lenses (eyeglasses or contact lenses). Astigmatism correction can usually be easily incorporated into eye glasses. Alternatively, special soft contact lenses called toric lenses can be prescribed. Soft toric lenses have greater light-bending power in one direction than the other. Another option, particularly for higher amounts of astigmatism, is a gas-permeable rigid contact lens. After performing various tests, your eye doctor will determine the ideal prescription for your astigmatism.

Refractive surgery. Another method for correcting astigmatism is changing the shape of the cornea through refractive or laser eye surgery. While there is more than one type of refractive surgery, specific treatments are recommended on an individual basis. Refractive surgeries require healthy eyes that are free from retinal problems, corneal scars, and any eye disease.